A7 P17D400 - DSG

[Aaaa7]

Hi

I have the following code displayed (P17D400) along with the message ‘gearbox malfunction you may continue driving’ which happens on occasion.

I’ve researched this and obviously the DSG’s are a mine field, however I’m hoping the fact I can list the issues below may help identify further:

- it can take a second or two to select gear D1 and if on a hill it will judder pulling away

- If it can’t select D1 it goes to D2 with the ‘malfunction message and won’t change up or down from D2

- reverse is a similar story and won’t always select 

 

all the above issues are temporarily resolved by turning the car on and off again, it is worth noting that If it’s taking a second or so to select D1 and I apply some accelerator then it sometimes engages quite violently and lurches forward and then all good and continues up through the gears and I can travel 100’s of miles with no issue, it’s only that R and D1.

 

anyone with some knowledge or similar experiences I’d be grateful for a reply and I’ll be sure to keep this updated with developments.

I’ve read about solenoids potentially causing this or could a clutch pack be more likely?

 

Thanks in advance 

[Steve Q]

Solenoids can be a problem or the module. However the first thing I'd look at is when was the gearbox oil last changed? 

Degrading/old oil can affect the gearbox to change gears effectively. 

[Aaaa7]

Hi 

thanks for the reply. The gearbox oil was changed when the problem started as a first port of call, I also tried the reset (hold the accelerator down for 30 secs etc)

Are the solenoids independent from the mechatronic unit or built within them? Is it better to replace the mechatronic unit or do the new units not come with the new solenoids? 

Thanks again for any help 👍
 

 

Edited July 15, 2023 by Aaaa7

[Aaaa7]

Also if anyone would know if the clutch pressure solenoids N439 and N435 are part of the mechatronic unit or seperate?  Apologies, my knowledge on this isn’t great but I’m thinking clutch pressure solenoids first followed by mechatronic unit replacement if not  and also a check of the common cable I’ve read about that leaks from the coolant in to the gearbox selector or ecu.